Polymer compounds and a preparation method thereof

ABSTRACT

Disclosed herein are polymer compounds, a method for preparing thereof. More specifically, provided are polymer compounds with well-connected, narrow size distribution free-volume element and a method for preparing the polymer compounds by thermal rearrangement for aromatic polyimides containing ortho-positioned functional groups in the solid state.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to polymer compounds and a preparationmethod thereof. More specifically, the present invention relates topolymer compounds with well-connected, narrow size distributionfree-volume element and a method for preparing the polymer compounds bythermal rearrangement of aromatic polyimides containing ortho-positionedfunctional groups in the solid state.

(b) Description of the Related Art

Small-molecule and ion diffusion through cavities (i.e., free-volumeelements) in soft organic materials is an inherently subnano- ornanoscopic phenomenon. It has important implications for membraneseparation processes in chemicals production as well as energyconversion and storage applications [e.g., pharmaceutical separations(B. Jeong et al., Nature 1997, 388, 860), organic batteries (P.Lightfoot et al., Science 1993, 262, 883), fuel cells (M. A. Hickner etal., Chem. Rev. 2004, 104, 4587), and gas separation (H. Lin et al.,Science 2006, 311, 639)]. Transport of small gas molecules throughpolymers occurs by diffusion through transient free-volume elements orcavities formed by random, thermally stimulated motion of the flexibleorganic chains.

Unlike pore sizes and shapes in rigid microporous inorganic materialssuch as zeolites (Z. Lai et al., Science 2003, 300, 456) and carbonmolecular sieve materials (H. B. Park et al., Adv. Mater. 2005, 17,477), cavity sizes and shapes are not uniform in amorphous polymers. Thecavity radius (r) of the most selective polymers such as polyimides,polysulfones, and polycarbonates, as measured by positron annihilationlifetime spectroscopy (PALS), is 0.3 nm or less with a broaddistribution of cavity sizes, and gas permeability is rather low (Y.Yampolskii, I. Pinnau, B. D. Freeman, Materials Science of Membranes forGas and Vapor Separation (Wiley, London, 2006).

Conversely, the most permeable polymer, poly(1-trimethylsilyl-1-propyne)(PTMSP), exhibits an approximately bimodal cavity size distributioncentered at around r=0.3 nm and r=0.6 to 0.7 nm (K. Nagai et al., Polym.Sci. 2001, 26, 721). The high concentration of large cavities and thehigh connectivity among cavities results in very high permeability for apolymer, but its ability to separate small molecules (kinetic diameter<0.45 nm) is too low to be useful, and the large cavities collapse overtime due to physical aging (K. Nagai et al., Polym. Sci. 2001, 26, 721).Thus, among known polymers, free-volume element size and distributionplay a key role in determining permeability and separationcharacteristics. However, the broad size range of free-volume elementsin such materials precludes the preparation of polymers having both highpermeability and high selectivity.

The inventors of the present invention demonstrate that polymers with anintermediate cavity size, a narrow cavity size distribution, and a shapereminiscent of bottlenecks connecting adjacent chambers, such as thosefound elegantly in nature in the form of ion channels (D. A. Doyle etal., Science 1998, 280) and aquaporins (D. Kozono et al., Invest. 2002,109, 1395), yield both high permeability and high selectivity. Centralto approach for preparing these intermediate-sized cavities iscontrolled free-volume element formation through spatial rearrangementof the flat, rigid-rod structure with high-torsional energy barriers torotation between two rings (V. J. Vasudevan, J. E. McGrath,Macromolecules 1996, 29, 637). The stiff, rigid ring units in such flattopologies pack efficiently, leaving very small penetrant accessiblefree-volume elements. This tight packing is also promoted byintersegmental interactions such as charge-transfer complexes betweenheteroatoms containing lone electron pairs (e.g., O, S and N) (W. J.Welsh, D. Bhaumik, J. E. Mark, Macromolecules 1981, 14, 947). Thegenesis of these materials was the demand for highly thermally andchemically stable polymers. However, their application as gas separationmembranes was frustrated by their lack of solubility in common solvents,which effectively prevents them from being prepared as thin membranes bysolvent casting, which is the most widely practiced method for membranepreparation.

Consequently, the present inventors suggested that completely aromatic,insoluble, infusible polymers can be prepared from highly solubleprecursors by irreversible molecular rearrangement at about 350° C. to450° C. for aromatic polyimides containing ortho-positioned functionalgroups (e.g., —OH, —SH and —NH₂) [H. B. Park, C. H. Jung, Y. M. Lee etal., Polymers with cavities tuned for fast selective transport of smallmolecules and ions, Science 2007, 318, 254. 38]. In addition, thepresent inventors ascertained that aromatic polymers interconnected withheterocyclic rings (e.g., benzoxazole, benzothiazole and benzopyrrolone)showed higher gas permeation performance due to their well-controlledfree-volume element formation by thermal rearrangement in the solidstate.

SUMMARY OF THE INVENTION

Therefore, the present invention has been made in view of the aboveproblems, and it is an object of the present invention to providepolymer compounds with well-connected cavities, an intermediate cavitysize and a narrow cavity size distribution.

It is another object of the present invention to provide a method forpreparing the polymer compounds by thermally treating aromaticpolyimides containing ortho-positioned functional groups (e.g.,polyhydroxyimide, polythiolimide, and polyaminoimide).

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is showing two types of changes in chain structure occur duringthe rearrangement;

FIG. 2 is FT-IR spectra of polymer compounds of Example 3 andComparative Example 1;

FIG. 3 is FT-IR spectra of polymer compounds of Example 9 andComparative Example 2;

FIG. 4 is FT-IR spectra of polymer compounds of Example 10 andComparative Example 3;

FIG. 5 is a TGA-MS thermogram of polyhydroxyimide of Comparative Example1 and Examples 1, 3 and 4;

FIG. 6 is a TGA-MS thermogram of polythiolimide of Comparative Example 2(precursor of Example 9) and Example 9;

FIG. 7 is a TGA-MS thermogram of polyaminoimide of Comparative Example 3(precursor of Example 10) and Example 10;

FIG. 8 is nitrogen adsorption/desorption isotherms at −196° C. forExamples 3, 9 and 10;

FIG. 9 is nitrogen adsorption/desorption isotherms at −196° C. forExamples 3, 5, 6, 7 and 8;

FIG. 10 is a graph showing cavity radius distribution of Examples 1 to 3and Comparative Example 1 measured by PALS;

FIG. 11 is a graph comparing oxygen permeability (Barrer) andoxygen/nitrogen selectivity for flat films prepared in Examples 1 to 11,14 to 18, 20 to 30 of the present invention and Comparative Examples 1to 10 (the numbers 1 to 11, 14 to 18, 20 to 30 indicate Examples 1 to11, 14 to 18, 20 to 30, respectively; and the numbers Comp. 1 to Comp.10 indicate Comparative Examples 1 to 10, respectively); and

FIG. 12 is a graph comparing carbon dioxide permeability (Barrer) andcarbon dioxide/methane selectivity for flat prepared in Examples 1 to11, 14 to 18, 20 to 30 of the present invention and Comparative Examples1 to 7, 10 (the numbers 1 to 11, 14 to 18, 20 to 30 indicate Examples 1to 11, 14 to 18, to 30, respectively; and the numbers Comp. 1 to Comp.7, Comp. 10 indicate Comparative Examples 1 to 7, 10, respectively).

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, the present invention will be illustrated in more detail.

In one aspect, the present invention is directed to polymer compoundscontaining at least one repeating unit represented by Formulae 1 to 14below:

In Formulae 1 to 14,

Ar₁ is a tetravalent C₅-C₂₄ arylene group or a tetravalent C₅-C₂₄heterocyclic ring, which is substituted or unsubstituted with at leastone substituent selected from the group consisting of C₁-C₁₀ alkyl,C₁-C₁₀ alkoxy, C₁-C₁₀ haloalkyl and C₁-C₁₀ haloalkoxy, or two or more ofwhich are fused together to form a condensation ring or covalentlybonded to each other via a functional group selected from the groupconsisting of O, S, C(═O), CH(OH), S(═O)₂, Si(CH₃)₂, (CH₂)_(p) (in which1≦p≦10), (CF₂)_(q), (in which 1≦q≦10), C(CH₃)₂, C(CF₃)₂ and C(═O)NH;

Ar₁′ and Ar₂ are identical to or different from each other and are eachindependently a bivalent C₅-C₂₄ arylene group or a bivalent C₅-C₂₄heterocyclic ring, which is substituted or unsubstituted with at leastone substituent selected from the group consisting of C₁-C₁₀ alkyl,C₁-C₁₀ alkoxy, C₁-C₁₀ haloalkyl and C₁-C₁₀ haloalkoxy, or two or more ofwhich are fused together to form a condensation ring or covalentlybonded to each other via a functional group selected from the groupconsisting of O, S, C(═O), CH(OH), S(═O)₂, Si(CH₃)₂, (CH₂)_(p) (in which1≦p≦10), (CF₂)_(q), (in which 1≦q≦10), C(CH₃)₂, C(CF₃)₂ and C(═O)NH;

Q is O, S, C(═O), CH(OH), S(═O)₂, Si(CH₃)₂, (CH₂)_(p) (in which 1≦p≦10),(CF₂)_(q), (in which 1≦q≦10), C(CH₃)₂, C(CF₃)₂, C(═O)NH, C(CH₃)(CF₃),C₁-C₆ alkyl-substituted phenyl or C₁-C₆ haloalkyl-substituted phenyl inwhich Q is linked to opposite both phenyl rings in the position of m-m,m-p, p-m or p-p;

Y″ is —O or S;

n is an integer from 20 to 200;

m is an integer from 10 to 400; and

l is an integer from 10 to 400.

Ar₁ and Ar₂ may be the same arylene or heterocyclic ring. Preferably,Ar₁ is selected from the following compounds and the linkage positionthereof includes all of o-, m- and p-positions.

wherein X is O, S, C(═O), CH(OH), S(═O)₂, Si(CH₃)₂, (CH₂)_(p) (in which1≦p≦10), (CF₂)_(q), (in which 1≦q≦10), C(CH₃)₂, C(CF₃)₂, or C(═O)NH; Wis O, S or C(═O); and Z₁, Z₂ and Z₃ are identical to or different fromeach other and are O, N or S.

More preferably, Ar₁ is selected from the following compounds:

Preferably, Ar₂ is selected from the following compounds and the linkageposition thereof includes all of o-, m- and p-positions.

wherein X is O, S, C(═O), CH(OH), S(═O)₂, Si(CH₃)₂, (CH₂)_(p) (in which1≦p≦10), (CF₂)_(q), (in which 1≦q≦10), C(CH₃)₂, C(CF₃)₂, or C(═O)NH; Wis O, S or C(═O); and Z₁, Z₂ and Z₃ are identical to or different fromeach other and are O, N or S.

More preferably, Ar₂ is selected from the following compounds:

Preferably, Q is CH₂, C(CH₃)₂, C(CF₃)₂, O, S, S(═O)₂ or C(═O).

More preferably, Ar₁ is,

Ar₂ is

and Q is C(CF₃)₂.

Preferably, the polymer compounds have a fractional free volume (FFV) of0.18 to 0.40, a d-spacing of 0.58 to 0.80 nm and a cavity radiusdifference of 0.1 to 0.4 Å between maximum cavity radius and minimumcavity radius.

The polymer compounds of the present invention may be doped with anacid. By adding small acidic dopants, the cavity size and shape of thepolymer compounds can be tuned. For example, after doping, the CO₂permeability decreases but CO₂/CH₄ selectivity increases.

Suitable acidic dopant for use with the present invention includessulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, HBrO₃,HClO₄, HPF₆, HBF₆, 1-methyl-3-methylimidazolium cation (BMIM⁺) andmixtures thereof.

Preferably, the polymer compounds of the present invention areorganic-inorganic composite polymers via incorporation of inorganicoxides or inorganic fillers into the polymer matrix. Here, theorganic-inorganic composite polymers can be prepared by adding aninorganic oxides or inorganic fillers to polyamic acid or polyimidewhich is subsequently subjected to imidization and thermal-treating oronly thermal-treating.

Suitable inorganic oxides for use with the present invention includefumed silica, zirconium oxide, tetraethoxy silane, montmorillonite clayand mixtures thereof. Here, the preferable content of the inorganicoxide is 0.1 to 10% by weight, based on the total weight of theorganic-inorganic composite polymer compound. When the amount ofinorganic oxide is less 0.1% by weight, the effect of adding theinorganic oxide is too low to expect the improvement of mechanical,thermal, and chemical stabilities. Conversely, when the amount ofinorganic oxide exceeds 10% by weight, excessive amount of inorganicoxides cause the composite polymer compounds to rapidly lose themechanical strength and to be broken.

Suitable inorganic fillers for use with the present invention includephosphotungstic acid (PWA), phosphomolybdenic acid, silicotungstic acid(SiWA), molybdophosphoric acid, silicomolybdic acid, phosphotin acid,zirconium phosphate (ZrP) and mixtures thereof. Here, the preferablecontent of the inorganic fillers is 0.5 to 60% by weight, based on thetotal weight of the organic-inorganic composite polymer compound. Whenthe amount of inorganic filler is less 0.5% by weight, the effect ofadding the inorganic filler is too low to expect the improvement ofmechanical, thermal, and chemical stabilities. Conversely, when theamount of inorganic filler exceeds 60% by weight, excessive amount ofinorganic fillers cause the composite polymer compounds to rapidly losethe mechanical strength and to be broken.

The polymer compounds of the present invention have well-connectedhourglass shaped cavities, and narrow cavity size distribution. Thesefree-volume elements are appropriate for molecular and ionic transportand molecular separations.

According to Experimental Example 5 of the present invention, thenitrogen absorption/desorption isotherm analysis indicates the presenceof substantial amounts of free volume.

With reference to Experimental Example 6 of the present invention, itcan be seen from PALS analysis that a precursor polymer [ComparativeExample 1, synthesized from 4,4′-(hexafluoroisopropylidene)-diphthalicanhydride (6FDA) and 2,2′-bis(3-amino-4-hydroxylphenyl)hexafluoropropane (bisAPAF) via thermal imidization up to 300° C.] andits corresponding thermally rearranged polymers [Examples 1 to 3]undergoes microstructural change depending on the extent ofrearrangement.

In detail, the cavity radius of a precursor polymer (which is centeredat about 0.28 nm and is very broad) increases to 0.3 to 0.4 nm, and thedistribution of cavity sizes becomes narrow as the thermal rearrangementtemperature increases to 450° C. (see FIG. 10).

PALS analysis reveals an increase in o-positronium (o-Ps) lifetime asrearrangement temperature increases from 300 to 450° C. (see Table 4).In general, longer o-Ps lifetime indicates larger cavity sizes (B. R.Wilks et al., J. Polym. Sci. Part B: Polym. Phys. 2003, 41, 2185). Theo-Ps intensity (%) increases by 700% as thermal rearrangementtemperature is increased to 400° C., but decreases above thistemperature. Notably, despite increasing o-Ps lifetime, the reduction ofo-Ps intensity in the sample treated at 450° C. (Example 3) indicatesthat an increase in mean cavity size is accompanied by a decrease in thenumber of cavities, suggesting coalescence of smaller cavities to formlarger ones. Hourglass shaped cavities, having narrow neck regionsseparating much larger adjacent chambers, are consistent with the aboveresults.

To have excellent separation properties, the small neck regions must notbe too large relative to the size of the molecules being separated,because large openings enable relatively nonselective flow mechanisms(e.g., Knudsen flow) (Y. Yampolskii, I. Pinnau, B. D. Freeman, MaterialsScience of Membranes for Gas and Vapor Separation (Wiley, London,2006)). However, large cavities adjoining the necks will contribute tohigh rates of molecular transport. The large cavity size of the fullyconverted sample (Example 3) is smaller than that of PTMSP (0.675 nm)but substantially larger than that of common glassy polymers (e.g.,0.286 nm for polysulfone; 0.289 nm for polycarbonate) (B. R. Wilks etal., J. Polym. Sci. Part B: Polym. Phys. 2003, 41, 2185). Similarbehavior is observed in other precursor polymers prepared by acombination of other monomers based on the same methodology.

Referring to Experimental Example 7, it can be confirmed that thepolymer compounds of the present invention demonstrate excellent O₂/N₂and CO₂/CH₄ separation performance, surpassing the O₂/N₂ and CO₂/CH₄separation limitation of typical polymer membranes (See FIGS. 11 to 12).Counter intuitively, the O₂ permeability, O₂/N₂ selectivity and the CO₂permeability, CO₂/CH₄ selectivity are both high, in contrast to thebehavior of conventional strongly size-sieving polymer membranes, wherehigh CO₂/CH₄ selectivity invariably leads to low CO₂ permeability (B. D.Freeman, Macromolecules 1999, 32, 375). On the permeability-selectivitymap, the separation performance of the polymer films according to thepresent invention is intermediate between the performance of commonpolymers and carbon molecular sieve membranes. As revealed by PALS inExperimental Example 6, the unusual microstructure of the polymercompounds according to the present invention (i.e., large cavities)provides an explanation for their high gas permeabilities, and theconstriction formed by cavity coalescence is presumably responsible fortheir precise discrimination among gas molecules such as CO₂ and CH₄. Asshown above, the polymer compounds of the present invention showsuperior gas permeability and gas selectivity. Therefore, the polymercompounds of the present invention are suitable for use in thepreparation of gas separation, vapor separation, water purification, lowdielectric constant materials, adsorbents, thermostable fiber, films,and so forth in a variety of forms such as powders, films, fibers andhollow fibers.

With reference to Experimental Example 8 of the present invention, itcan be seen that after the thermal rearrangement through the thermaltreatment, the polymer compounds of the present invention undergomorphological change including reduced density, considerably increasedfractional free volume due to increased microcavity size and increasedd-spacing, as compared to the precursor polymers. As a result, thepolymer compounds exhibit considerably high gas permeability, ascompared with the precursor polymers.

There are two advantages to the polymer compounds of the presentinvention.

First, the precursor polyimides (i.e., polyhydroxyimide, polythiolimide,polyaminoimide) are soluble in common solvents; that is, they can beprepared in the various forms (e.g., hollow fibers) and thencontinuously exposed to heat treatment because these polymer compoundsproduce tough, ductile, robust films rather than brittle, fragilespecimens such as zeolite or carbon membranes. This feature markedlyenhances their potential utility and ultimate reduction to practice.

Second, it is much easier and simpler to coat these organic polymercompounds without any defects or cracks onto microporous ceramic supportmembranes for the large scale production of membranes than to coatinorganic materials such as zeolite, silica, and carbon membranes ontosuch supports. Most of all, the greatest benefit of the polymercompounds according to the present invention is the ability to tune thecavity size and distribution of organic polymers for specific gasapplications, vapor separation, water purification, low dielectricconstant materials, adsorbents, thermostable fiber, films, and so forthby using various templating molecules and heat treatments, with onestarting material.

In another aspect, the present invention is directed to a method forpreparing the polymer compound comprising:

thermally treating polyimides represented by the following Formulae 15to 32.

In Formulae 15 to 32,

Ar₁ is a tetravalent C₅-C₂₄ arylene group or a tetravalent C₅-C₂₄heterocyclic ring, which is substituted or unsubstituted with at leastone substituent selected from the group consisting of C₁-C₁₀ alkyl,C₁-C₁₀ alkoxy, C₁-C₁₀ haloalkyl and C₁-C₁₀ haloalkoxy, or two or more ofwhich are fused together to form a condensation ring or covalentlybonded to each other via a functional group selected from the groupconsisting of O, S, C(═O), CH(OH), S(═O)₂, Si(CH₃)₂, (CH₂)_(p) (in which1≦p≦10), (CF₂)_(q), (in which 1≦q≦10), C(CH₃)₂, C(CF₃)₂ and C(═O)NH;

Ar₂ is a bivalent C₅-C₂₄ arylene group or a bivalent C₅-C₂₄ heterocyclicring, which is substituted or unsubstituted with at least onesubstituent selected from the group consisting of C₁-C₁₀ alkyl, C₁-C₁₀alkoxy, C₁-C₁₀ haloalkyl and C₁-C₁₀ haloalkoxy, or two or more of whichare fused together to form a condensation ring or covalently bonded toeach other via a functional group selected from the group consisting ofO, S, C(═O), CH(OH), S(═O)₂, Si(CH₃)₂, (CH₂)_(p) (in which 1≦p≦10),(CF₂)_(q), (in which 1≦q≦10), C(CH₃)₂, C(CF₃)₂ and C(═O)NH;

Q is O, S, C(═O), CH(OH), S(═O)₂, Si(CH₃)₂, (CH₂)_(p) (in which 1≦p≦10),(CF₂)_(q) (in which 1≦q≦10), C(CH₃)₂, C(CF₃)₂, C(═O)NH, C(CH₃)(CF₃),C₁-C₆ alkyl-substituted phenyl or C₁-C₆ haloalkyl-substituted phenyl inwhich Q is linked to opposite both phenyl rings in the position of m-m,m-p, p-m or p-p;

Y is —OH, —SH or —NH₂;

Y′ is different from Y and is —OH, —SH or —NH₂;

n is an integer from 20 to 200;

m is an integer from 10 to 400; and

l is an integer from 10 to 400.

Ar₁ and Ar₂ may be the same arylene or heterocyclic ring.

Preferably, Ar₁ is selected from the following compounds and the linkageposition thereof includes all of o-, m- and p-positions.

wherein X is O, S, C(═O), CH(OH), S(═O)₂, Si(CH₃)₂, (CH₂)_(p) (in which1≦p≦10), (CF₂)_(q), (in which 1≦q≦10), C(CH₃)₂, C(CF₃)₂, or C(═O)NH; Wis O, S or C(═O); and Z₁, Z₂ and Z₃ are identical to or different fromeach other and are O, N or S.

More preferably, Ar₁ is selected from the following compounds:

Preferably, Ar₂ is selected from the following compounds and the linkageposition thereof includes all of o-, m- and p-positions.

wherein X is O, S, C(═O), CH(OH), S(═O)₂, Si(CH₃)₂, (CH₂)_(p) (in which1≦p≦10), (CF₂)_(q), (in which 1≦q≦10), C(CH₃)₂, C(CF₃)₂, or C(═O)NH; Wis O, S or C(═O); and Z₁, Z₂ and Z₃ are identical to or different fromeach other and are O, N or S.

More preferably, Ar₂ is selected from the following compounds:

Preferably, Q is CH₂, C(CH₃)₂, C(CF₃)₂, O, S, S(═O)₂ or C(═O).

More preferably, Ar₁ is

Ar₂ is

and Q is C(CF₃)₂.

The method for preparing the polymer compounds comprising irreversiblemolecular rearrangement at about 350° to 500° C. for aromatic polyimidescontaining ortho-positioned functional groups (e.g., —OH, —SH and —NH₂)through intramolecular and intermolecular conversion.

The representative method of these can be explained throughpolyhydroxyimide containing ortho-positioned hydroxyl group andpolythiolimide containing ortho-positioned thiol group as a startingmaterials.

With reference to FIG. 1, two types of changes in chain structure occurduring the rearrangement that alter chain packing: (i) random chainconformations resulting from the formation of meta- and para-linkedchains (See FIG. 1A); and (ii) relatively flexible, twisting pairs ofshort flat planes (α and β) that convert to single long flat planes (γ)(See FIG. 1B) that are much more rigid than those of the parent moieties[e.g., the torsional angle (φ2) of benzoxazole-phenylene ring is closeto 0° at the energy-minimized state because the coplanar conformation isfavored due to resonance stabilization].

The use of stiff, rigid chain elements (e.g., benzoxazole-phenylenering, benzothiazole-phenylene ring or benzopyrrolone-phenylene ring)prevents large intrachain, indiscriminant torsional rotation, increasesthe efficiency of cavity formation, and inhibits rapid collapse of thecreated cavities. These materials are thermally stable, and thestructural rearrangements occurring during this process do notcorrespond to partial rigid polymer chain segments in the solid state.

The polyimides represented by Formulae 15 to 18 are thermally rearrangedthrough a preparation process which will be mentioned later, to beconverted polybenzoxazole, polybenzothiazole and polybenzopyrrolone,each having a high fractional free volume. Here, the polybenzoxazole isprepared from polyhydroxyimide in which Y is —OH, the polybenzothiazoleis prepared from polythiolimide in which Y is —SH, and thepolybenzopyrrolone is prepared from polyaminoimide in which Y is —NH₂.

In addition, the polyimide copolymers represented by Formulae 19 to 22are thermally rearranged to be converted benzoxazole-imide copolymer,benzothiazole-imide copolymer or benzopyrrolone-imide copolymers whichhave a high fractional free volume. Here, it is possible to controlphysical properties of the thermally rearranged polymer compounds bycontrolling the copolymerization ratio between blocks which will bethermally rearranged into polybenzoxazole, polybenzothiazole andpolybenzopyrrolone, and blocks which will be thermally rearranged intopolyimides.

In addition, the polyimide copolymers represented by Formulae 23 to 32are thermally rearranged to be converted copolymers of polybenzoxazole,polybenzothiazole and polybenzopyrrolone, each having a high freevolume. Here, it is possible to control the physical properties ofthermally rearranged polymer compounds thus prepared can be controlledby controlling the copolymerization ratio between blocks which arethermally rearranged into polybenzoxazole, polybenzothiazole andpolybenzopyrrolone.

Preferably, the copolymerization ratio between the blocks, m:l, is from0.1:9.9 to 9.9:0.1, more preferably 2:8 to 8:2, most preferably 5:5. Thecopolymerization ratio affects the morphology of the thermallyrearranged polymer compounds thus prepared. Since such morphologicchange is associated with free volume elements, gas permeability andselectivity, it is considerably important to control thecopolymerization ratio.

The thermal treatment is carried out under an inert atmosphere at 350 to500° C., preferably 400 to 450° C., for 1 minute to 12 hours, preferably10 minutes to 2 hours at a heating rate of 1 to 10° C./min. When thetemperature is below this range, the thermal rearrangement is notcompleted and the polyimide precursor remains unreacted, causingdeterioration in purity. On the other hand, when the temperature exceedsthis range, polyimide is disadvantageously converted into a carbonsubstance as an inorganic due to polymer carbonization. Accordingly, itis preferable that the thermal treatment be suitably performed withinthis temperature range.

The thermal treatment of the present invention will be illustrated indetail with reference to Reaction Schemes 1 and 2 below:

In Reaction Schemes 1 and 2, Ar₁, Ar₁′, Ar₂, Q, Y, Y″, n, m, and l aredefined as above.

As can be seen from Reaction Scheme 1, the polyimides represented by theFormulae 15 to 18 are converted through thermal treatment intopolybenzoxazole, polybenzothiazole, polybenzopyrrolone represented bythe Formulae 1 to 7. The conversion of polyimide into the thermallyrearranged polymer compounds is carried out through the removal reactionof CO₂ or H₂O present in the polymers of Formulae 15 to 18.

At this time, the polyimides of Formulae 15 to 18 in which Y is —OH or—SH (i.e., polyhydroxyimide or polythiolimide) are thermally rearrangedinto polybenzoxazoles (Y″═O) or polybenzothiazoles (Y″═S) of Formula 1,Formula 3, Formula 5 and Formula 6. In addition, polyimides of Formulae1 to 4 in which Y is —NH₂ (i.e., polyaminoimide) are thermallyrearranged into polybenzopyrrolones of Formulae 2, 4 and 7.

As can be seen from Reaction Scheme 2, through the afore-mentionedthermal treatment, polyimide copolymers of Formulae 19 to 22 areconverted through the removal reaction of CO₂ present in the polyimidesinto polymer compounds of Formulae 8 to 14.

At this time, polyimide copolymers of Formulae 19 to 22 in which Y is—OH or —SH are thermally rearranged into benzoxazole(Y″═O)-imidecopolymers or benzothiazole(Y″═S)-imide copolymers of Formulae 8, 10, 12and 13. In addition, polyimide copolymers of Formulae 19 to 22 in whichY is —NH₂ are thermally rearranged into benzopyrrolone-imide copolymersof Formulae 9, 11 and 14.

The blocks constituting polyimide copolymers represented by Formulae 23to 32 are thermally rearranged into polybenzoxazole, polybenzothiazoleand polybenzopyrrolone, depending upon the type of Y to be convertedinto copolymers thereof, i.e., copolymers of polymers represented byFormulae 1 to 7.

The polyimides of Formulae 15 to 18, polyimide copolymers of Formulae 19to 32 can be prepared in accordance with methods well known in the art.For example, the polyimide and the polyimide copolymer may be preparedby imidizing and cyclizing hydroxyl group (—OH) containing polyamic acid(i.e., polyhydroxyamic acid), thiol group containing polyamic acid(i.e., polythiolamic acid) or amine group (—NH₂) containing polyamicacid (i.e., polyaminoamic acid) or copolymers thereof.

According to examples of the present invention, as depicted in ReactionSchemes 3 and 4 below, polyamic acids represented by Formulae 33 to 50are imidized are then prepared into polyimides represented by Formulae15 to 18, polyimide copolymers represented by Formulae 19 to 32.

The polyamic acids of Formulae 33 to 50 can be prepared in accordancewith methods well known in the art. For example, the polyamic acids maybe prepared by reacting tetracarboxylic acid anhydrides as monomers witharomatic diamines containing —OH, —SH or —NH₂.

As can be seen from Reaction Scheme 3, polyamic acids (i.e.,polyhydroxyamic acid, polythiolamic acid and polyaminoamic acid)represented by the Formula 33, Formula 34, Formula 35 and Formula 36 areconverted through imidization i.e., cyclization reaction into polyimidesrepresented by Formula 15, Formula 16, Formula 17 and Formula 18,respectively.

In addition, polyamic acid copolymers represented by the Formula 37,Formula 38, Formula 39 and Formula 40 are converted through imidizationinto polyimide copolymers represented by Formula 19, Formula 20, Formula21 and Formula 22, respectively.

As can be seen from Reaction Scheme 4, polyamic acid copolymersrepresented by the Formulae 41 to 50 are converted through imidizationinto polyimide copolymers represented by Formulae 23 to 32.

The imidization can be conducted in accordance with methods well knownin the art. Representative examples of the imidization include chemicalimidization, thermal imidization and solution-thermal imidization.

Preferably, the chemical imidization is carried out at 10 to 180° C. for1 to 48 hours. At this time, acetic anhydride can be added to removewater as a byproduct along with pyridine as a catalyst.

Preferably, the thermal imidization is carried out under an inertatmosphere or vacuum state at 100 to 300° C. for 1 minute to 24 hoursafter casting the polymeric solution onto a glass plate.

In addition, preferably, the solution-thermal imidization is carried outin solution at 80 to 250° C. for 1 to 48 hours.

When the imidization temperature is below this range, polyamic acid as aprecursor is only slightly imidized, and on the other hand, when theimidization temperature exceeds this range, significant effects cannotbe obtained and economic efficiency is thus very low. The imidizationconditions may be suitably controlled within the range according to thefunctional groups, Ar₁, Ar₂, Q and Y.

EXAMPLES

Hereinafter, preferred examples will be provided for a furtherunderstanding of the invention. These examples are for illustrativepurposes only and are not intended to limit the scope of the presentinvention.

Example 1

A benzoxazole represented by Formula 51 was prepared as follows.

A 250 ml reactor fitted with a teflon stirring system, an inlet for annitrogen gas and placed in an oil bath to constantly maintain thereaction temperature at room temperature. The reactor was charged with3.66 g (10 mmol) of 2,2′-bis(3-amino-4-hydroxy-phenyl)hexafluoropropaneand N-methylpyrrolidone (NMP) as a solvent. 4.44 g (10 mmol) of4,4′-(hexafluoroisopropylidene)diphthalic anhydride was slowly addedinto the solution. Then, the solution was allowed to react for about 4hours to prepare a pale yellow viscous polyhydroxyamic acid solution.

The solution was cast on a glass plate and cured in vacuum oven for 2hours at 100° C., 1 hour for 150° C., 1 hour for 200° C., and 1 hour for250° C.

Then, vacuum drying was carried out in a vacuum oven at 60° C. for 24hours in order to completely remove the residual solvent. Consequently,the transparent brownish polyhydroxyimide film (4 cm×4 cm in size; 20-50μm in thickness) was obtained. The polyhydroxyimide film was placed inthe middle of a quartz tube, and thermally treated in the muffledtubular furnace at 350° C. at a heating rate of 5° C./min under argonflow (100 cm³[STP]/min). Films were held for one hour at 350° C. andthen cooled down slowly to room temperature.

As a result of FT-IR analysis, characteristic bands of the resultingpolybenzoxazole at 1,553, 1,480 cm⁻¹ (C═N) and 1,058 cm⁻¹ (C—O) whichwere not detected in polyhydroxyimide were confirmed.

Example 2

A polybenzoxazole was prepared in the same manner as in Example 1,except that the polyhydroxyimide film was thermally treated at 400° C.

As a result of FT-IR analysis, characteristic bands of the resultingpolybenzoxazole at 1,553, 1,480 cm⁻¹ (C═N) and 1,058 cm⁻¹ (C—O) whichwere not detected in polyhydroxyimide were confirmed.

Example 3

A polybenzoxazole was prepared in the same manner as in Example 1,except that the polyhydroxyimide film was thermally treated at 450° C.

As a result of FT-IR analysis, characteristic bands of the resultingpolybenzoxazole at 1,553, 1,480 cm⁻¹ (C═N) and 1,058 cm⁻¹ (C—O) whichwere not detected in polyhydroxyimide were confirmed.

Example 4

A polybenzoxazole was prepared in the same manner as in Example 1,except that the polyhydroxyimide film was thermally treated at 500° C.

As a result of FT-IR analysis, characteristic bands of the resultingpolybenzoxazole at 1,553, 1,480 cm⁻¹ (C═N) and 1,058 cm⁻¹ (C—O) whichwere not detected in polyhydroxyimide were confirmed.

Example 5

A polybenzoxazole represented by Formula 52 was prepared in the samemanner as in Example 3, except that 2.94 g (10 mmol) of3,3′,4,4′-biphenyltetracarboxylic dianhydride as starting materials werereacted with 3.66 g (10 mmol) of2,2′-bis(3-amino-4-hydroxy-phenyl)hexafluoropropane.

As a result of FT-IR analysis, characteristic bands of the resultingpolybenzoxazole at 1,553, 1,480 cm⁻¹ (C═N) and 1,058 cm⁻¹ (C—O) whichwere not detected in polyhydroxyimide were confirmed.

Example 6

A polybenzoxazole represented by Formula 53 was prepared in the samemanner as in Example 3, except that 3.10 g (10 mmol) of4,4′-oxydiphthalic anhydride as starting materials were reacted with3.66 g (10 mmol) of 2,2′-bis(3-amino-4-hydroxy-phenyl)hexafluoropropane.

As a result of FT-IR analysis, characteristic bands of the resultingpolybenzoxazole at 1,553, 1,480 cm⁻¹ (C═N) and 1,058 cm⁻¹ (C—O) whichwere not detected in polyhydroxyimide were confirmed.

Example 7

A polybenzoxazole represented by Formula 54 was prepared in the samemanner as in Example 3, except that 2.18 g (10 mmol) of1,2,4,5-benzenetetracarboxylic dianhydride as starting materials werereacted with 3.66 g (10 mmol) of2,2′-bis(3-amino-4-hydroxy-phenyl)hexafluoropropane.

As a result of FT-IR analysis, characteristic bands of the resultingpolybenzoxazole at 1,553, 1,480 cm⁻¹ (C═N) and 1,058 cm⁻¹ (C—N) whichwere not detected in polyhydroxyimide were confirmed.

Example 8

A polybenzoxazole represented by Formula 55 was prepared in the samemanner as in Example 3, except that 3.22 g (10 mmol) of3,3′,4,4′-benzophenone tetracarboxylic dianhydride as starting materialswere reacted with 3.66 g (10 mmol) of2,2′-bis(3-amino-4-hydroxy-phenyl)hexafluoropropane.

As a result of FT-IR analysis, characteristic bands of the resultingpolybenzoxazole at 1,553, 1,480 cm⁻¹ (C═N) and 1,058 cm⁻¹ (C—O) whichwere not detected in polyhydroxyimide were confirmed.

Example 9

A polybenzothiazole represented by Formula 56 was prepared in the samemanner as in Example 3, except that 4.44 g (10 mmol) of4,4′-(hexafluoroisopropylidene)diphthalic anhydride as startingmaterials were reacted with 2.08 g (10 mmol) of2,5-diamino-1,4-benzenedithiol dihydrochloride.

As a result of FT-IR analysis, characteristic bands of the resultingpolybenzothiazole at 1,484 cm⁻¹ (C—S) and 1,404 cm⁻¹ (C—S) which werenot detected in polythiolimide were confirmed.

Example 10

A polybenzopyrrolone represented by Formula 57 was prepared in the samemanner as in Example 3, except that 4.44 g (10 mmol) of4,4′-(hexafluoroisopropylidene)diphthalic anhydride as startingmaterials were reacted with 2.14 g (10 mmol) of 3,3′-diaminobenzidine.

As a result of FT-IR analysis, characteristic bands of the resultingpolybenzopyrrolone at 1,758 cm⁻¹ (C═O) and 1,625 cm⁻¹ (C═N) which werenot detected in polyaminoimide were confirmed.

Example 11

A polybenzoxazole represented by Formula 58 was prepared in the samemanner as in Example 3, except that 2.68 g (10 mmol) of1,4,5,8-naphthalenic tetracarboxylic dianhydride as starting materialswere reacted with 3.66 g (10 mmol) of2,2′-bis(3-amino-4-hydroxy-phenyl)hexafluoropropane.

As a result of FT-IR analysis, characteristic bands of the resultingpolybenzoxazole at 1,553, 1,480 cm⁻¹ (C═N) and 1,058 cm⁻¹ (C—O) whichwere not detected in polyhydroxyimide were confirmed.

Example 12 Chemical Imidization

A 250 ml reactor fitted with a teflon stirring system, an inlet for annitrogen gas and placed in an oil bath to constantly maintain thereaction temperature at room temperature. The reactor was charged with3.66 g (10 mmol) of 2,2′-bis(3-amino-4-hydroxy-phenyl)hexafluoropropaneand N-methylpyrrolidone (NMP) as a solvent. 4.44 g (10 mmol) of4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) was slowlyadded into the solution. After 4 hours of vigorous stirring, 1.61 ml (20mmol) of pyridine and 1.89 ml (20 mmol) of acetic anhydride were addedto the solution as catalyst for chemical imidization. Subsequently, theoil bath was heated to temperature of 80° C. and allowed to react forabout 24 hours to prepare a pale yellow viscous polyhydroxyimidesolution.

The solution was cast on a glass plate and cured in vacuum oven for 6hours at 180° C. Then, vacuum drying was carried out in a vacuum oven at60° C. for 24 hours in order to completely remove the residual solvent.Consequently, the transparent brownish polyhydroxyimide film (4 cm×4 cmin size; 20-50 μm in thickness) was obtained. The polyhydroxyimide filmwas placed in the middle of a quartz tube, and thermally treated in themuffled tubular furnace at 450° C. at a heating rate of 5° C./min underargon flow (100 cm³[STP]/min). Films were held for one hour at 450° C.and then cooled down slowly to room temperature.

As a result of FT-IR analysis, characteristic bands of the resultingpolybenzoxazole at 1,553, 1,480 cm⁻¹ (C═N) and 1,058 cm⁻¹ (C—O) whichwere not detected in polyhydroxyimide were confirmed.

Example 13 Solution-Thermal Imidization

A polybenzoxazole was prepared in the same manner as in Example 12,except that the pale yellow viscous polyhydroxyamic acid solution wasprepared without pyridine and acetic anhydride by solution-thermalimidization at 80° C. for 4 hour and 180° C. for 4 hour in solution.

As a result of FT-IR analysis, characteristic bands of the resultingpolybenzoxazole at 1,553, 1,480 cm⁻¹ (C═N) and 1,058 cm⁻¹ (C—O) whichwere not detected in polyhydroxyimide were confirmed.

Example 14

A 250 ml reactor fitted with a teflon stirring system, an inlet for annitrogen gas and placed in an oil bath to constantly maintain thereaction at room temperature. The reactor was charged with 3.66 g (10mmol) of 2,2′-bis(3-amino-4-hydroxy-phenyl)hexafluoropropane andN-methylpyrrolidone (NMP) as a solvent. 4.44 g (10 mmol) of4,4′-(hexafluoroisopropylidene) diphthalic anhydride was slowly addedinto the solution. Then, the solution was allowed to react for about 4hours to prepare a pale yellow viscous polyhydroxyamic acid solution.

The solution was cast on a glass plate and cured in vacuum oven for 2hours at 100° C., 1 hour for 150° C., 1 hour for 200° C., and 1 hour for250° C. Then, vacuum drying was carried out in a vacuum oven at 60° C.for 24 hours in order to completely remove the residual solvent.Consequently, the transparent brownish polyhydroxyimide film (4 cm×4 cmin size; 20-50 μm in thickness) was obtained. The polyhydroxyimide filmwas placed in the middle of a quartz tube, and thermally treated in themuffled tubular furnace at 350° C. at a heating rate of 5° C./min underargon flow (100 cm³[STP]/min). Films were held for one hour at 350° C.and then cooled down slowly to room temperature.

Then, the polybenzoxazole films were treated in 10M HCl solution at onehour, washed with distilled water, and dried at 150° C.

As a result of FT-IR analysis, characteristic bands of the resultingpolybenzoxazole at 1,553, 1,480 cm⁻¹ (C═N) and 1,058 cm⁻¹ (C—O) whichwere not detected in polyhydroxyimide were confirmed, and acharacteristic band of chlorine anion at 920 cm⁻¹ was also confirmed.

Example 15

A polybenzoxazole was prepared in the same manner as in Example 14,except adding a final process in which the thermally rearranged filmswere treated in 10M NaOH solution until the pH was set to 7.

As a result of FT-IR analysis, characteristic bands of the resultingpolybenzoxazole at 1,553, 1,480 cm⁻¹ (C═N) and 1,058 cm⁻¹ (C—O) whichwere not detected in polyhydroxyimide were confirmed, but acharacteristic band of chlorine anion at 920 cm⁻¹ was not confirmed.

Example 16

A polybenzoxazole was prepared in the same manner as in Example 14,except adding two final processes in which the thermally rearrangedfilms were treated in 10M NaOH solution until the pH was set to 7, andtreated again in 10M HCl solution at one hour, washed and dried at 150°C.

As a result of FT-IR analysis, characteristic bands of the resultingpolybenzoxazole at 1,553, 1,480 cm⁻¹ (C═N) and 1,058 cm⁻¹ (C—O) whichwere not detected in polyhydroxyimide were confirmed, and acharacteristic band of chlorine anion at 920 cm⁻¹ was also confirmed.

Example 17

A polybenzoxazole was prepared in the same manner as in Example 14,except that the 10 M HCl solution was substituted for 10 M H₃PO₄solution.

As a result of FT-IR analysis, characteristic bands of the resultingpolybenzoxazole at 1,553, 1,480 cm⁻¹ (C═N) and 1,058 cm⁻¹ (C—O) whichwere not detected in polyhydroxyimide were confirmed, and acharacteristic band of chlorine anion at 1,020 cm⁻¹ was also confirmed.

Example 18

Silica-dispersed solution with 5 weight percent was fabricated viadispersion of fumed silica powder (Aerosil 200) with average particlesize of 13 nm in N-methylpyrrolidone, and added with content of 1 weightpercent into the polyhydroxyamic acid solution in Example 3.

The polyhydroxyamic acid solution containing dispersed silica was caston a glass plate and cured in vacuum oven for 2 hours at 100° C., 1 hourfor 150° C., 1 hour for 200° C., and 1 hour for 250° C. Then, vacuumdrying was carried out in a vacuum oven at 60° C. for 24 hours in orderto completely remove the residual solvent. Consequently, the transparentbrownish polyhydroxyimide film (4 cm×4 cm in size; 20-50 μm inthickness) was obtained. The polyhydroxyimide film was placed in themiddle of a quartz tube, and thermally treated in the muffled tubularfurnace at 450° C. at a heating rate of 5° C./min under argon flow (100cm³[STP]/min). Films were held for one hour at 450° C. and then cooleddown slowly to room temperature.

As a result of FT-IR analysis, characteristic bands of the resultingpolybenzoxazole at 1,553, 1,480 cm⁻¹ (C═N) and 1,058 cm⁻¹ (C—O) whichwere not detected in polyhydroxyimide were confirmed.

Example 19

Zirconium phosphate-dispersed solution with 5 weight percent wasfabricated via dispersion of zirconium phosphate powder as a protonconductor in N-methylpyrrolidone as described in J. Membr. Sci. 2003,226, 169 and added with content of 20 weight percent into thepolyhydroxyamic acid solution in Example 3.

The polyhydroxyamic acid solution containing dispersed zirconiumphosphate was cast on a glass plate and cured in vacuum oven for 2 hoursat 100° C., 1 hour for 150° C., 1 hour for 200° C., and 1 hour for 250°C. Then, vacuum drying was carried out in a vacuum oven at 60° C. for 24hours in order to completely remove the residual solvent. Consequently,the transparent brownish polyhydroxyimide film (4 cm×4 cm in size; 20-50μm in thickness) was obtained. The polyhydroxyimide film was placed inthe middle of a quartz tube, and thermally treated in the muffledtubular furnace at 450° C. at a heating rate of 5° C./min under argonflow (100 cm³[STP]/min). Films were held for one hour at 450° C. andthen cooled down slowly to room temperature.

As a result of FT-IR analysis, characteristic bands of the resultingpolybenzoxazole at 1,553, 1,480 cm⁻¹ (C═N) and 1,058 cm⁻¹ (C—O) whichwere not detected in polyhydroxyimide were confirmed.

Example 20

A polybenzoxazole represented by Formula 59 was prepared in the samemanner as in Example 3, except that 4.44 g (10 mmol) of4,4′-(hexafluoroisopropylidene)diphthalic anhydride as startingmaterials were reacted with 2.16 g (10 mmol) of 3,3′-dihydroxybenzidine.

As a result of FT-IR analysis, characteristic bands of the resultingpolybenzoxazole at 1,553, 1,480 cm⁻¹ (C═N) and 1,052 cm⁻¹ (C—O) whichwere not detected in polyhydroxyimide were confirmed.

Example 21

A polybenzopyrrolone represented by Formula 60 was prepared in the samemanner as in Example 3, except that 3.10 g (10 mmol) of4,4′-oxydiphthalic anhydride as starting materials were reacted with2.84 g (10 mmol) of benzene-1,2,4,5-tetramine tetrahydrochloride.

As a result of FT-IR analysis, characteristic bands of the resultingpolybenzopyrrolone at 1,758 cm⁻¹ (C═O) and 1,625 cm⁻¹ (C═N), which werenot detected in polyaminoimide were confirmed.

Example 22

A benzoxazole copolymer (molar ratio of benzoxazole:benzoxazole=5:5)represented by Formula 61 was prepared in the same manner as in Example3, except that 5.88 g (20 mmol) of 3,3′,4,4′-biphenyltetracarboxylicanhydride as starting materials were reacted with 3.66 g (10 mmol) of2,2′-bis(3-amino-4-hydroxy-phenyl)hexafluoropropane and 2.16 g (10 mmol)of 3,3′-dihydroxybenzidine.

As a result of FT-IR analysis, characteristic bands of the resultingpolybenzoxazole at 1,553, 1,480 cm⁻¹ (C═N) and 1,058 cm⁻¹ (C—O) whichwere not detected in polyhydroxyimide were confirmed.

Example 23

A benzoxazole-imide copolymer (molar ratio of benzoxazole:imide=8:2)represented by Formula 62 was prepared in the same manner as in Example3, except that 6.45 g (20 mmol) of 3,3′,4,4′-benzophenonetetracarboxylicdianhydride as starting materials were reacted with 5.86 g (16 mmol) of2,2′-bis(3-amino-4-hydroxy-phenyl)hexafluoropropane and 0.8 g (4 mmol)of 4,4′-diaminodiphenylether.

As a result of FT-IR analysis, the resulting benzoxazole-imide copolymer(molar ratio of benzoxazole:imide=8:2) copolymer thus prepared showedcharacteristic bands of polybenzoxazole block at 1,553, 1,480 cm⁻¹ (C═N)and 1,058 cm⁻¹ (C—O), and characteristic bands of polyimide block at1,720 cm⁻¹ (C═O) and 1,580 cm⁻¹ (C═O).

Example 24

A benzopyrrolone-imide copolymer (molar ratio ofbenzopyrrolone:imide=8:2) represented by Formula 63 was prepared in thesame manner as in Example 3, except that 4.44 g (10 mmol) of4,4′-(hexafluoroisopropylidene)diphthalic anhydride as startingmaterials were reacted with 1.71 g (8 mmol) of 3,3′-diaminobenzidine and0.4 g (2 mmol) of 4,4′-diaminodiphenylether.

As a result of FT-IR analysis, the resulting benzopyrrolone-imidecopolymer (molar ratio of benzopyrrolone:imide=8:2) copolymer showedcharacteristic bands of polypyrrolone block at 1,758 cm⁻¹ (C═O) and1,625 cm⁻¹ (C═N) and characteristic bands of polyimide block at 1,720cm⁻¹ (C═O) and 1,580 cm⁻¹ (C═O).

Example 25

A benzothiazole-imide copolymer (molar ratio of benzothiazole:imide=8:2)represented by Formula 64 was prepared in the same manner as in Example3, except that 8.88 g (10 mmol) of4,4′-(hexafluoroisopropylidene)diphthalic anhydride as startingmaterials were reacted with 3.30 g (16 mmol) of2,5-diamino-1,4-benzenedithiol dihydrochloride and 0.8 g (4 mmol) of4,4′-diaminodiphenylether.

As a result of FT-IR analysis, the resulting benzothiazole-imidecopolymer (molar ratio of benzothiazole:imide=8:2) copolymer showedcharacteristic bands of polybenzothiazole block at 1,484 cm⁻¹ (C—S) and1,404 cm⁻¹ (C—S) and characteristic bands of polyimide block at 1,720cm⁻¹ (C═O) and 1,580 cm⁻¹ (C═O).

Example 26

A benzoxazole-thiazole copolymer (molar ratio ofbenzoxazole:thiazole=5:5) represented by Formula 65 was prepared in thesame manner as in Example 3, except that 2.94 g (10 mmol) of3,3′,4,4′-biphenyltetracarboxylic anhydride as starting materials werereacted with 1.08 g (5 mmol) of 3,3′-dihydroxybenzidine and 1.09 g (5mmol) of 2,5-diamino-1,4-benzenedithiol dihydrochloride.

As a result of FT-IR analysis, the resulting benzoxazole-thiazolecopolymer (molar ratio of benzoxazole:thiazole=5:5) copolymer showedcharacteristic bands of polybenzoxazole block at 1,595, 1,480 cm⁻¹ (C═N)and 1,052 cm⁻¹ (C—O), and characteristic bands of polybenzothiazoleblock at 1,484 cm⁻¹ (C—S) and 1,404 cm⁻¹ (C—S) which were not detectedin polyimide were confirmed.

Example 27

A benzopyrrolone copolymer (molar ratio ofbenzopyrrolone:benzopyrrolone=8:2) represented by Formula 66 wasprepared in the same manner as in Example 3, except that 8.88 g (20mmol) of 4,4′-(hexafluoroisopropylidene)diphthalic anhydride as startingmaterials were reacted with 3.42 g (16 mmol) of 3,3′-diaminobenzidineand 1.14 g (4 mmol) of benzene-1,2,4,5-tetramine tetrahydrochloride.

As a result of FT-IR analysis, characteristic bands of the resultingpolybenzopyrrolone at 1,758 cm⁻¹ (C═O) and 1,625 cm⁻¹ (C═N), which werenot detected in polyaminoimide, were confirmed.

Example 28

A benzoxazole-imide copolymer (molar ratio ofbenzoxazole:benzothiazole=5:5) represented by Formula 67 was prepared inthe same manner as in Example 3, except that 2.94 g (10 mmol) of3,3′,4,4′-biphenyltetracarboxylic dianhydride as starting materials werereacted with 1.83 g (5 mmol) of2,2′-bis(3-amino-4-hydroxy-phenyl)hexafluoropropane and 1.00 g (5 mmol)of 4,4′-diaminodiphenylether.

As a result of FT-IR analysis, the resulting benzoxazole-imide copolymer(molar ratio of benzoxazole:imide=5:5) copolymer thus prepared showedcharacteristic bands of polybenzoxazole block at 1,553, 1,480 cm⁻¹ (C═N)and 1,058 cm⁻¹ (C—O), and characteristic bands of polyimide block at1,720 cm⁻¹ (C═O) and 1,580 cm⁻¹ (C═O).

Example 29

A benzoxazole-imide copolymer (molar ratio of benzoxazole:imide=2:8) wasprepared in the same manner as in Example 28, except thatcopolymerization ratio of benzoxazole to imide was adjusted to 2:8.

Example 30

A benzoxazole-imide copolymer (molar ratio of benzoxazole:imide=8:2) wasprepared in the same manner as in Example 28, except thatcopolymerization ratio of benzoxazole to imide was adjusted to 8:2.

Comparative Example 1

A 250 ml reactor fitted with a teflon stirring system, an inlet for annitrogen gas and placed in an oil bath to constantly maintain thereaction temperature at room temperature. The reactor was charged with3.66 g (10 mmol) of 2,2′-bis(3-amino-4-hydroxy-phenyl)hexafluoropropaneand N-methylpyrrolidone (NMP) as a solvent. 4.44 g (10 mmol) of4,4′-(hexafluoroisopropylidene)diphthalic anhydride was slowly addedinto the solution. Then, the solution was allowed to react for about 4hours to prepare a pale yellow viscous polyhydroxyamic acid solution.

The solution was cast on a glass plate and cured in vacuum oven for 2hours at 100° C., 1 hour for 150° C., 1 hour for 200° C., and 1 hour for250° C. Then, vacuum drying was carried out in a vacuum oven at 60° C.for 24 hours in order to completely remove the residual solvent.Consequently, the transparent brownish polyhydroxyimide film (4 cm×4 cmin size; 20-50 μm in thickness) was obtained. The polyhydroxyimide filmwas placed in the middle of a quartz tube, and thermally treated in themuffled tubular furnace at 300° C. at a heating rate of 5° C./min underargon flow (100 cm³[STP]/min). Films were held for one hour at 300° C.and then cooled down slowly to room temperature.

Comparative Example 2

A polythiolimide was prepared in the same manner as in ComparativeExample 1, except that 4.44 g (10 mmol) of4,4′-(hexafluoroisopropylidene)diphthalic anhydride as startingmaterials were reacted with 2.08 g (10 mmol) of2,5-diamino-1,4-benzenedithiol dihydrochloride.

Comparative Example 3

A polyaminoimide was prepared in the same manner as in ComparativeExample 1, except that 4.44 g (10 mmol) of4,4′-(hexafluoroisopropylidene)diphthalic anhydride as startingmaterials were reacted with 2.14 g (10 mmol) of 3,3′-diaminobenzidine.

Comparative Example 4

A polybenzoxazole was prepared in the same manner as in ComparativeExample 1, except that 3.10 g (10 mmol) of 4,4′-oxydiphthalic anhydrideas starting materials were reacted with 3.66 g (10 mmol) of2,2′-bis(3-amino-4-hydroxy-phenyl)hexafluoropropane.

Comparative Example 5

A polybenzoxazole was prepared in the same manner as in ComparativeExample 1, except that 2.18 g (10 mmol) of1,2,4,5-benzenetetracarboxylic dianhydride as starting materials werereacted with 3.66 g (10 mmol) of2,2′-bis(3-amino-4-hydroxy-phenyl)hexafluoropropane.

Comparative Example 6

A polybenzoxazole was prepared in the same manner as in ComparativeExample 1, except that 3.22 g (10 mmol) of 3,3′,4,4′-benzophenonetetracarboxylic dianhydride as starting materials were reacted with 3.66g (10 mmol) of 2,2′-bis(3-amino-4-hydroxy-phenyl)hexafluoropropane.

Comparative Example 7

A polybenzoxazole was prepared in the same manner as in Example 3,except that 2.94 g (10 mmol) of 3,3′,4,4′-biphenyl tetracarboxylicdianhydride as starting materials were reacted with 3.66 g (10 mmol) of2,2′-bis(3-amino-4-hydroxy-phenyl)hexafluoropropane.

Comparative Example 8

A carbon molecular sieve film was prepared from carbonizing polyimide(Kapton®, Du Pont) at 600° C.

In detail, a commercial polyimide film prepared from equimolar1,2,4,5-benzenetetracarboxylic dianhydride and 4,4′-diaminodiphenyletheras starting materials was placed in the middle of a quartz tube, andthermally treated in the muffled tubular furnace at 600° C. at a heatingrate of 5° C./min under argon flow (100 cm³[STP]/min). Films were heldfor one hour at 600° C. and then cooled down slowly to room temperature.

Comparative Example 9

A carbon molecular sieve film was prepared in the same manner as inComparative Example 8, except that polyimide film (Kapton®, Du Pont) wascarbonized at 800° C.

Comparative Example 10

A carbon molecular sieve film was prepared from carbonizingpolyhydroxyimide of Comparative Example 1, except that thepolyhydroxyimide film was carbonized at 600° C.

Comparative Example 11

As described in J. Polym. Sci.: Part B: Polym. Phys. 30, 1215,2,2′-bis(trimethylsilylamino-4-trimethylsiloxy-phenyl)-1,1,1,3,3,3-hexafluoropropaneand hexafluoroisopropylidenebiphenyl-4,4-dicarboxylic acid chloride withthe same equivalent was dissolved in dimethylacetamide at 0° C., andreacted to obtain poly(o-hydroxyamide). The solution was cast on a glassplate and thermal-treated at 300° C. under an inert atmosphere.Consequently, polybenzoxazole film was obtained.

Experimental Example 1 FT-IR Analysis

In order to characterize precursor and polymer compounds, ATR-FTIRspectra were obtained using an Infrared Microspectrometer (IlluminatIR,SensIR Technologies, Danbury, Conn., USA).

FIG. 2 is FT-IR spectra of polymer compounds of Example 3 andComparative Example 1.

As can be seen from FIG. 2, in case of polyhydroxyimide of ComparativeExample 1, characteristic peak of HO-phenylene at 3,400 cm⁻¹,characteristic imide peaks at 1,788 cm⁻¹ and 1,618 cm⁻¹ were observed,In addition, characteristic carbonyl group peak was observed at 1,720cm⁻¹. On the other hand, in case of polybenzoxazole of Example 3,characteristic benzoxazole peaks were observed at 1,553, 1,480 and 1,052cm⁻¹. It can be confirmed from FT-IR spectra that polyhydroxyimide ofComparative Example 1 was converted to polybenzoxazole of Example 3 bythermal treatment.

In addition, Examples 1, 2, 5 to 8, 11 to 20 and 22 which contain thesimilar structure and same functional groups to Example 3, andComparative Examples 4 to 7 to Comparative Example 1 showed the samespectra with Example 3 and Comparative Example 1, respectively.

FIG. 3 is FT-IR spectra of polymer compounds of Example 9 andComparative Example 2.

As shown in FIG. 3, in case of polythiolimide of Comparative Example 2,characteristic broad and weak band of —SH at 2,400 to 2,600 cm⁻¹,characteristic imide peaks at 1,793 cm⁻¹ and 1,630 cm⁻¹ andcharacteristic carbonyl group peak at 1,720 cm⁻¹ were observed. On theother hand, in case of polybenzothiazole of Example 9, characteristicbenzothiazole peaks were observed at 1,480 and 1,404 cm⁻¹. It can beconfirmed from FT-IR spectra that polythiolimide of Comparative Example2 was converted to polybenzothiazole of Example 9 by thermal treatment.

FIG. 4 is FT-IR spectra of polymer compounds of Example 10 andComparative Example 3.

As can be seen from FIG. 4, in case of polyaminoimide of ComparativeExample 3, characteristic broad and weak band of —NH₂ at 2,900 to 3,400cm⁻¹, characteristic imide peaks at 1,793 cm⁻¹ and 1,630 cm⁻¹ andcharacteristic carbonyl group peak at 1,720 cm⁻¹ were observed. On theother hand, in case of polybenzopyrrolone of Example 10, characteristicpolybenzopyrrolone peaks were observed at 1,758 (C═O) and 1,625 cm⁻¹(C═N). It can be confirmed from FT-IR spectra that polyaminoimide ofComparative Example 3 was converted to polybenzopyrrolone of example 10by thermal treatment.

In addition, Examples 21 and 27 which contain the similar structure andsame functional groups to Example 10 showed the same infrared spectrawith Example 10.

Experimental Example 2 Thermogravimetric Analysis/Mass Spectroscopy(TGA-MS)

The polyimides of Comparative Example 1, 2, and 3, the polybenzoxazolesof Examples 1, 3 and 4, the polybenzothiazole of Example 9, and thepolybenzopyrrolone of Example 10 were subjected to thermogravimetricanalysis/mass spectroscopy (TGA-MS) to confirm the weight loss occurredfrom the thermal rearrangement. The TGA-MS was carried out using TG 209F1 Iris and QMS 403C Aeolos (NETZSCH, Germany), while injecting Ar intoeach precursor membrane. At this time, heating rate was 10° C./min andAr purge flow was 90 cm³ (STP)/min. The results thus obtained are shownin FIGS. 5, 6 and 7.

FIG. 5 is a TGA-MS thermogram of polyhydroxyimide of Comparative Example1 and polybenzoxazole of Examples 1, 3 and 4.

As can be seen from FIG. 5, the thermal degradation of thepolybenzoxazoles of Examples 3 and 4 is not observed within the thermalconversion temperature of 400 to 500° C. On the other hand, thepolyhydroxyimide of Comparative Example 1 and the polybenzoxazole ofExample 1 began to be thermally arranged at a thermal conversiontemperature of 400 to 500° C. The polybenzoxazole of Example 1 which wastreated at 350° C., a relatively lower temperature to complete thethermal conversion process, showed further conversion at the temperaturerange of 400 to 500° C. The evolved gas component was subjected to MS toconfirm the presence of CO₂. According to elimination of CO₂, the weightof polyhydroxyimide of Comparative Example 1 and polybenzoxazole ofExample 1 decreased 6 to 8%, 4 to 5% respectively at the temperaturerange of 400 to 500° C. due to the thermal rearrangement through thermaltreatment, but the weight of polybenzoxazoles of Examples 3 and 4 didnot decrease to 500° C.

In addition, Examples 2, 5 to 8, 11 to 20 and 22 which contain thesimilar structure and same functional groups to Example 3, andComparative Examples 4 to 7 to Comparative Example 1 showed the similarthermal decomposition curves to Example 3 and Comparative Example 1,respectively. FIG. 6 is a TGA-MS thermogram of polythiolimide ofComparative Example 2 (precursor of Example 9) and Example 9.

As can be seen from FIG. 6, the thermal degradation of thepolybenzothiazole of Example 9 is not observed within the thermalconversion temperature of 400 to 500° C. On the other hand, thepolythiolimide of Comparative Example 2 began to be thermally rearrangedat a temperature range of 400 to 500° C. The evolved gas component wassubjected to MS to confirm the presence of CO₂. According to eliminationof CO₂, the weight of polythiolimide of Comparative Example 2 decreased12 to 14% at the temperature range of 400 to 500° C. due to the thermalrearrangement through thermal treatment, but the weight ofpolybenzothiazoles of Example 9 did not decrease to 500° C.

FIG. 7 is a TGA-MS thermogram of polyaminoimide of Comparative Example 3(precursor of Example 10) and Example 10.

As can be seen from FIG. 7, the thermal degradation of thepolybenzopyrrolone of Example 10 is not observed within the thermalconversion temperature of 300 to 500° C. On the other hand, thepolyaminoimide of Comparative Example 3 began to be thermally rearrangedat a temperature range of 300 to 500° C. The evolved gas component wassubjected to MS to confirm the presence of H₂O. According to eliminationof H₂O. The weight of polyaminoimide of Comparative Example 3 decreased7 to 9% at the temperature range of 300 to 500° C. due to the thermalrearrangement through thermal treatment, but the weight ofpolybenzothiazole of Example 10 did not decrease to 500° C.

In addition, Examples 21 and 27 which contain the similar structure andsame functional groups to Example 10 showed the similar thermaldecomposition curves to Example 10.

From these data, we can see that thermal resistance of the presentinvention thermally treated at high temperature is very good.

Experimental Example 3 Elemental analysis

To observe structure change of the polymer compounds of Examples 1 to 4and Comparative Example 1, elemental analyzer (Carlo Erba/Fison Inc,ThermoFinnigan EA1108) was engaged, WO₃/Cu was engaged as a catalyst,BBOT (2,5-bis(5-tert-butyl-benzoxazole-2-yl) thiophene) was engaged asStandard material. Table 1 shows the test result of examples at 1000° C.

TABLE 1 polymer Formula C (wt %) H (wt %) N (wt %) O (wt %) F (wt %) Ex.1 — 54.1 ± 0.16 2.07 ± 0.00 3.87 ± 0.01 9.34 ± 0.18 30.6 ± 0.02 Ex. 2 —55.2 ± 0.01 2.02 ± 0.01 4.05 ± 0.00 7.23 ± 0.03 31.5 ± 0.04 Ex. 3[C₃₂H₁₄F₁₂N₂O₂]n 56.7 ± 0.01 1.93 ± 0.02 4.21 ± 0.01 4.89 ± 0.12 32.3 ±0.12 (55.9)* (2.06)* (4.08)* (4.66)* (33.2)* Comp. [C₃₄H₁₄F₁₂N₂O₆]n 53.2± 0.08 1.87 ± 0.06 3.62 ± 0.01 11.3 ± 0.22 30.0 ± 0.08 Ex. 1 (52.7)*(1.82)* (3.62)* (11.3)* (29.4)* *Calculated value Measured usingThermoFinnigan (Carlo Erba/Fison) EA1108 Temperature: 1000° C., (1060°C. for O₂) Catalyst: WO₃/Cu (Nickel plated carbon, nickel wool, quartzturnings, soda lime, magnesium perchlorate anhydrone for O) Sample mass:5 mg, (2 mg for O) Measured elements: C, H, N, O Standard material: BBOT(2,5-bis(5-tert-butyl-benzoxazole-2-yl) thiophene), (sulfanilamide forO)

Referring table 1, polyhydroxyimide of Comparative Example 1 must becomprised of 52.7% C, 1.82% H, 3.62% N, 11.3% O, 29.4% F in theabstract. The constituents of polyhydroxyimide of Comparative Example 1(53.2±0.08% C, 1.87±0.06% H, 3.62±0.01% N, 11.3±0.22% O, 30.0±0.08% F)was consistent with the above theoretic polyhydroxyimide constituents.

In addition, polybenzoxazole of Example 3 must be comprised of 55.9% C,2.06% H, 4.08% N, 4.66% O, 33.2% F in the abstract. The constituents ofpolybenzoxazole of example 3 (56.7±0.01% C, 1.93±0.02% H, 4.21±0.01% N,4.89±0.12% O, 32.3±0.12% F) was consistent with the above theoreticpolybenzoxazole constituents.

From these data, we can confirm that the formula of the thermallyrearranged polymer compounds of the present invention is consistent withthe supposed chemical formula.

Experimental Example 4 Mechanical Properties

The Mechanical properties of the precursor and polymer films shown weremeasured at 25° C. using AGS-J 500N (shimadzu). Five specimens of eachsample were tested. Standard deviation from the mean was within ±5%. Theresults thus obtained are shown in Table 2.

TABLE 2 Tensile Elongation strength percent at Sample (MPa) break (%)Ex. 1 87 3.8 Ex. 2 95 3.5 Ex. 3 98 3.9 Ex. 4 101 3.2 Ex. 5 96 4.7 Ex. 6104 4.2 Ex. 7 109 3.1 Ex. 8 103 4.1 Ex. 9 95 5.7 Ex. 10 88 4.2 Ex. 11 963.7 Ex. 12 92 5.2 Ex. 13 88 2.6 Ex. 20 117 4.2 Ex. 21 109 5.3 Ex. 22 985.9 Ex. 23 84 6.7 Ex. 24 91 5.5 Ex. 25 101 4.5 Ex. 26 96 3.2 Ex. 27 883.8 Ex. 28 96 5.2 Ex. 29 82 6.7 Ex. 30 95 4.3 Comp. Ex. 1 83 3.1 Comp.Ex. 2 76 4.2 Comp. Ex. 3 75 4.8 Comp. Ex. 4 81 3.5 Comp. Ex. 5 90 2.5Comp. Ex. 6 78 3.3 Comp. Ex. 7 85 3.1 Comp. Ex. 8 42 0.4 Comp. Ex. 9 520.3 Comp. Ex. 10 34 0.6

As can be seen from Table 2, the polymer compounds of the presentinvention showed better tensile strength and elongation percent thanthat of Comparative Example, because the polyimide main chain structurewas changed into stiff and rigid aromatic-connected polybenzoxazolestructure through thermal rearrangement. Therefore, it is advantageousthat the polymer compounds of the present invention can endure harshconditions such as long operation temperature, acidic conditions andhigh humidity due to the rigid polymer backbone present in the polymercompounds.

Experimental Example 5 Adsorption and Desorption Isotherm Analysis

This experiment was performed to determine N₂ adsorption/desorptioncharacteristics of the polymer compounds according to the presentinvention. N₂ adsorption isotherms of the polymer compounds weremeasured by a BET method. The results thus obtained are shown in FIGS. 8to 9.

FIG. 8 is nitrogen adsorption/desorption isotherms at −196° C. forExamples 3, 9 and 10. FIG. 9 is nitrogen adsorption/desorption isothermsat −196° C. for Examples 3, 5, 6, 7 and 8.

As shown in FIGS. 8 and 9, the nitrogen adsorption/desorption isothermof the present invention are the irreversible Type I form withhysteresis. This result confirmed that mesopores were formed accessiblefrom micropores.

In order to realize more precise characterization, the pore volume ofpolymer compounds according to the present invention was measured usinga specific surface area and pore analyzer (ASAP2020, Micromeritics, GA,USA). At this time, the polymer compounds were transferred topre-weighed analytic tubes which were capped with Transeal™ to preventpermeation of oxygen and atmospheric moisture during transfers andweighing. The polymer compounds were evacuated under dynamic vacuum upto 300° C. until an outgas rate was less than 2 mTorr/min. The resultsare shown in Table 3 below.

Specific surface area and total pore volume were calculated by measuringnitrogen adsorption degree until saturated pressure (P/P_(o)=1) by thecm³/g unit and using liquefied nitrogen at 77K through Equations 1 to 2well-known as Brunauer-Emmett-Teller (BET) within 0.05<P/P_(o)<0.3.

$\begin{matrix}{\frac{1}{\upsilon \left\lbrack {\left( {P_{0}/P} \right) - 1} \right\rbrack} = {{\frac{c - 1}{\upsilon_{m}}\left( \frac{P}{P_{0}} \right)} + \frac{1}{\upsilon_{m}c}}} & {{Equation}\mspace{14mu} 1}\end{matrix}$

In the Equation 1, P is balance pressure of gas, P₀ is saturatedpressure of gas, v is quantity of gas adsorbed, v_(m) is quantity of gasadsorbed at single phase at adsorption temperature, and c is BETconstant of Equation 2.

$\begin{matrix}{c = {\exp \left( \frac{E_{1} - E_{L}}{RT} \right)}} & {{Equation}\mspace{14mu} 2}\end{matrix}$

In the Equation 2, E₁ is adsorption heat at first phase, and E_(L) isadsorption heat beyond second phase, R is a gas constant, and T ismeasuring temperature.

TABLE 3 Maximum adsorption total pore volume quantity BET surface areaat a single point sample (cm³/g [STP]) (m²/g) (cm³/g [STP]) Ex. 1 3.582.73 0.002 Ex. 2 16.9 31.47 0.023 Ex. 3 219.2 661.5 0.335 Ex. 4 236.7638.2 0.309 Ex. 5 185.5 545.5 0.283 Ex. 6 24.8 59.78 0.036 Ex. 7 195.9556.1 0.290 Ex. 8 174.4 492.0 0.257 Ex. 9 145.8 409.9 0.223 Ex. 10 173.2532.9 0.266 Ex. 11 209.5 592.8 0.297 Ex. 12 163.9 457.6 0.239 Ex. 13142.8 352.8 0.213 Ex. 20 89.2 76.4 0.096 Ex. 21 117.6 92.7 0.141 Comp.Ex. 1 23.4 9.97 0.018 Comp. Ex. 2 68.6 44.8 0.072 Comp. Ex. 3 14.7 27.90.19

As can be seen from Table 3, the BET surfaces area of Example 3 aremarkedly large for polymers, 661.5 m² g⁻¹, total pore volume at a singlepoint are 0.335 cm³ g⁻¹. It indicates the presence of substantial amountof free volume.

Experimental Example 6 Positron Annihilation Lifetime Spectroscopy(PALS) Measurements

The PALS measurements were performed in nitrogen at ambient temperatureusing an automated EG&G Ortec fast-fast coincidence spectrometer. Thetiming resolution of the system was 240 ps. The polymer films werestacked to a thickness of 1 mm on either side of a ²²Na—Ti foil source.There was no source correction needed for the Ti foil (thickness 2.5μm). Each spectrum consisted of approximately 10 million integratedcounts. The spectra were modeled as the sum of three decayingexponentials or as a continuous distribution. The shortest lifetime, T₁,was fixed at 0.125 ns, which is characteristic of para-positroniumself-annihilation. The second lifetime, T₂, was approximately 0.35-0.45ns for all samples, characteristic of free and trapped positrons. Thelonger lifetime, T₃, was >1 ns and attributed to annihilations of oPs inthe free volume elements of the polymer.

Positron annihilation lifetime spectroscopy (PALS) is an instrumentmeasuring 0.511 MeV of 2-γ signals regarding β+ positron disappearanceby combining with electron in the pore. β+ positron is emitted duringradioisotope decay of ²²Na to ²²Ne. The size of pore can be calculatedthrough Equation 3 using disappearance time of 0.511 MeV of 2-γ signals.

$\begin{matrix}{\tau_{o - {Ps}} = {\frac{1}{2}\left\lbrack {1 - \frac{R}{R + {\Delta \; R}} + {\frac{1}{2\; \pi}{\sin \left( \frac{2\; \pi \; R}{R + {\Delta \; R}} \right)}}} \right\rbrack}^{- 1}} & {{Equation}\mspace{14mu} 3}\end{matrix}$

In the Equation 3, T_(o-Ps) is disappearance time of positron (ns), R ispore size, and ΔR is empirical parameter of the supposition that thepore is sphere.

The results thus obtained are shown in FIG. 10 and Table 4.

TABLE 4 Treated Intensity I₃ Lifetime Temperature polymers [%] [T₃/ns]FWHM* [° C.] Ex. 1 4.6 2.3 0.14 350 Ex. 2 14.3 3.2 0.12 400 Ex. 3 8.03.3 0.17 450 Comp. Ex. 1 2.0 2.0 0.48 300 *FWHM, full width at halfmaximum from the o-PS lifetime T₃ distribution

FIG. 10 is a graph snowing cavity radius distribution of Examples 1 to 3and Comparative Example 1 measured by PALS.

Micropore size and uniformity can be seen from FIG. 10 and Table 4.Polymer compound of Comparative Example 1 has wide distribution area andsmall quantity of pore as conventional polymers. But polymer compound ofExample 1 has narrow distribution area and large quantity of pore sizeof about 3.2 Å. And polymer compounds of Examples 2 to 3 have narrowdistribution area and large quantity of pore size of 3.7-3.8 Å generatedby thermal conversion. The reason why the numbers of pores decrease inExample 3 rather than Example 2 is that the pores are linked to eachother at a higher thermal conversion temperature, and explains theconnectivity of the micropores.

Experimental Example 7 Gas Permeability Measurements

In order to ascertain gas permeability and selectivity of Examples 1 to11, 14 to 18, 20 to 30 and Comparative Examples 1 to 10, the followingprocesses were performed using a high-vacuum time-lag apparatus (thecalibrated downstream volume was 30 cm³, the upstream and the downstreampressures were measured using a Baratron transducer with a full scale of33 and 0.002 atm, respectively). The results are shown in Table 5 andFIGS. 11 and 12.

All pure gas permeation tests were performed at 35° C. more than fivetimes, and the standard deviation from the mean values of thepermeabilities was within ±2%. The sample-to-sample reproducibility wasvery good, within ±5%. The effective area of the membranes was 4.00 cm².

For theses pure gases, it is possible to measure either the volume ofpermeate at fixed pressure or the rate of rise of permeate pressure in afixed receiver volume. The pressure at permeate, p₂, has very smallvalue (<2 Torr) while the pressure at inlet, p₁, is atmospheric pressureor more. While the pressure at permeate side was measured by recordingof p₂ versus time(sec), it is capable of approximating thepermeabilities of gas molecules through the thin films. The permeabilitycoefficient of A molecules, P_(A), can be calculated from the rate atwhich the downstream pressure increases in the fixed permeate volume atthe steady state as follows;

$\begin{matrix}{P_{A} = {\frac{Vl}{p_{1}{ART}}\left( \frac{p_{2}}{t} \right)_{ss}}} & {{Equation}\mspace{14mu} 4}\end{matrix}$

where V is the volume of fixed downstream receiver, l is the filmthickness, A is the film area, p₁ and p₂ are the pressures in theupstream and downstream, respectively, R, T and t are the gas constant,temperature and time, respectively.

TABLE 5 H₂ O₂ CO₂ CO₂/ perme- perme- perme- O₂/N₂ CH₄ ability abilityability selec- selec- (GPU) (GPU) (GPU) tivity tivity Ex. 1 60.9 5.523.6 6.9 26.2 Ex. 2 372.4 59.8 296.9 5.1 61.2 Ex. 3 2855.9 776.1 3575.35 44.3 Ex. 4 8867.5 1547.2 5963.2 6.5 40.7 Ex. 5 443.5 92.8 596.9 4.740.5 Ex. 6 91.2 14.3 72.79 6.1 58.2 Ex. 7 634.9 148.2 951.8 4.4 40.7 Ex.8 356.4 81.4 468.6 5.4 45.5 Ex. 9 2560 524.5 1251.3 5.9 61.4 Ex. 495.384.4 442 4.5 37.2 10 Ex. 4671.3 900.6 4111.5 5.5 62.5 11 Ex. 1231 236.5912.3 5.8 61.6 14 Ex. 1061.5 250.1 759.3 4.5 37.2 15 Ex. 941.8 203.3701.9 4.6 41.3 16 Ex. 738 82.4 295.1 6.8 89.4 17 Ex. 445.4 82.1 392.24.4 31.3 18 Ex. 53 3.5 12 8.3 54.5 20 Ex. 135.4 39.7 171.4 6.5 49.1 21Ex. 742.3 122.1 461.7 5.5 38.5 22 Ex. 491.6 107 389.1 4.2 19.5 23 Ex.300.1 59.7 314.4 5.5 40.3 24 Ex. 350.4 89.6 451.3 5.6 41 25 Ex. 2699.8650.1 2604.1 5.4 30.2 26 Ex. 752.1 150.4 429.5 5.5 23 27 Ex. 192.7 12.5251.9 4.9 28.6 28 Ex. 8.6 2.2 11.4 5.7 38.2 29 Ex. 294.2 106.6 388.9 4.219.4 30 Comp. 35.2 2.6 9.9 7.2 123.4 Ex. 1 Comp. 14.3 1.8 8.5 6.5 48.2Ex. 2 Comp. 206.8 22.7 80.2 5.9 38 Ex. 3 Comp. 12.2 0.8 1.8 13 110.7 Ex.4 Comp. 42.8 3.7 17 6.8 79.5 Ex. 5 Comp. 11.1 0.6 1.43 6.6 47.4 Ex. 6Comp. 14.3 0.7 2.7 7.7 90.6 Ex. 7 Comp. 534 383 1820 4.7 — Ex. 8 Comp.248 34.8 128 11.5 — Ex. 9 Comp. 4973.9 401.5 1140.7 7.65 50.2 Ex. 10

FIGS. 11 and 12 are the graphs comparing oxygen permeability (Barrer),oxygen/nitrogen selectivity and carbon dioxide permeability (Barrer) andcarbon dioxide/methane selectivity for flat films prepared in Examples 1to 11, 14 to 18, 20 to 30 of the present invention and ComparativeExamples 1 to 10 (the numbers 1 to 11, 14 to 18, 20 to 30 indicateExamples 1 to 11, 14 to 18, 20 to 30, respectively; and the numbersComp. 1 to Comp. 10 indicate Comparative Examples 1 to 10,respectively).

In the two plots, these microporous materials of the present inventshowed superior gas permeabilities with proper selectivities due to thewell-organized free volumes of these polymers, and most of them exceededthe conventional polymeric upperbounds well-known to an imaginarylimitation for certain gas mixtures [L. M. Robeson, Correlation ofseparation factor versus permeability for polymeric membrane, J. Membr.Sci., 1991, 62, 165, L. M. Robeson, The upper bound revisited, J. Membr.Sci., 2008, 320, 390].

Experimental Example 8 Fractional Free Volume

The fractional free volume of the precursor and polymer compounds wasmeasured.

Density of polymer is related with degree of free-volume, has aninfluence on transmittance.

First, density of the membranes was measured by a buoyancy method usinga Sartorius LA 310S analytical balance in accordance with Equation 5.

$\begin{matrix}{\rho_{P} = {\frac{w_{a}}{w_{a} - w_{w}} \times \rho_{w}}} & {{Equation}\mspace{14mu} 5}\end{matrix}$

In the Equation 5, ρ_(p) is density of polymer, ρ_(w) is density ofdeionized water, ω_(a) is weight of polymer measured in the air, ω_(w)is weight of polymer measures in the deionized water.

The fractional free volume (FFV, V_(f)) was calculated from the data inaccordance with Equation 6 below [W. M. Lee. Selection of barriermaterials from molecular structure. Polym Eng Sci. 1980; 20:65-9].

$\begin{matrix}{{FFV} = \frac{V - {1.3\; {Vw}}}{V}} & {{Equation}\mspace{14mu} 6}\end{matrix}$

wherein V is the polymer specific volume and V_(W) is the specific Vander Waals volume. The Van der Waals volume was estimated by a Cerius 4.2program using a synthia module based on the work of J. Bicerano [J.Bicerano. Prediction of polymer properties, Third Edition. Marcel DekkerInc. 2002].

The d-spacing was calculated in accordance with Bragg's equation fromX-ray diffraction pattern results.

TABLE 6 Volume Increment d- Density (V, V_(w) in FFV spacing sample(g/cm³) cm³/g) (cm³/g) FFV (V_(f)) (%) (nm) Comp. 1.503 0.665 0.4300.159 65 0.548 Ex. 1 Ex. 3 1.293 0.773 0.439 0.263 0.600 Comp. 1.4530.688 0.459 0.134 64 0.546 Ex. 7 Ex. 5 1.271 0.787 0.473 0.219 0.606Comp. 1.469 0.681 0.455 0.131 57 0.503 Ex. 4 Ex. 6 1 .304 0.767 0.4690.205 0.611 Comp. 1.478 0.677 0.443 0.148 28 0.560 Ex. 5 Ex. 7 1.3620.734 0.457 0.190 0.698 Comp. 1.482 0.675 0.457 0.120 102 0.539 Ex. 6Ex. 8 1.240 0.806 0.470 0.243 0.602 Comp. 1.475 0.678 0.373 0.172 640.576 Ex. 3 Ex. 10 1.406 0.711 0.610 0.282 0.634

As can be seen from Table 6, porosity in the polymer matrix of thepresent invention greatly increased from the result that V_(f) ofExample 3, 5 to 8, 10 compared with Comparative Examples 1, 3 to 7increased 28% to 102% due to the decrease in density of Example 3, 5 to8, 10 after thermal treatment.

1. A polymer compound containing at least one repeating unit representedby the following Formulae 1 to 14:

In Formulae 1 to 14, Ar₁ is a tetravalent C₅-C₂₄ arylene group or atetravalent C₅-C₂₄ heterocyclic ring, which is substituted orunsubstituted with at least one substituent selected from the groupconsisting of C₁-C₁₀ alkyl, C₁-C₁₀ alkoxy, C₁-C₁₀ haloalkyl and C₁-C₁₀haloalkoxy, or two or more of which are fused together to form acondensation ring or covalently bonded to each other via a functionalgroup selected from the group consisting of O, S, C(═O), CH(OH), S(═O)₂,Si(CH₃)₂, (CH₂)_(p) (in which 1≦p≦10), (CF₂)_(q), (in which 1≦q≦10),C(CH₃)₂, C(CF₃)₂ and C(═O)NH; Ar₁′ and Ar₂ are identical to or differentfrom each other and are each independently a bivalent C₅-C₂₄ arylenegroup or a bivalent C₅-C₂₄ heterocyclic ring, which is substituted orunsubstituted with at least one substituent selected from the groupconsisting of C₁-C₁₀ alkyl, C₁-C₁₀ alkoxy, C₁-C₁₀ haloalkyl and C₁-C₁₀haloalkoxy, or two or more of which are fused together to form acondensation ring or covalently bonded to each other via a functionalgroup selected from the group consisting of O, S, C(═O), CH(OH), S(═O)₂,Si(CH₃)₂, (CH₂)_(p) (in which 1≦p≦10), (CF₂)_(q), (in which 1≦q≦10),C(CH₃)₂, C(CF₃)₂ and C(═O)NH; Q is O, S, C(═O), CH(OH), S(═O)₂,Si(CH₃)₂, (CH₂)_(p) (in which 1≦p≦10), (CF₂)_(q), (in which 1≦q≦10),C(CH₃)₂, C(CF₃)₂, C(═O)NH, C(CH₃)(CF₃), C₁-C₆ alkyl-substituted phenylor C₁-C₆ haloalkyl-substituted phenyl in which Q is linked to oppositeboth phenyl rings in the position of m-m, m-p, p-m or p-p; Y″ is —O orS; n is an integer from 20 to 200; m is an integer from 10 to 400; and lis an integer from 10 to
 400. 2. The polymer compound according to claim1, wherein Ar₁ is selected from the following compounds:

wherein X is O, S, C(═O), CH(OH), S(═O)₂, Si(CH₃)₂, (CH₂)_(p) (in which1≦p≦10), (CF₂)_(q), (in which 1≦q≦10), C(CH₃)₂, C(CF₃)₂, or C(═O)NH; Wis O, S or C(═O); and Z₁, Z₂ and Z₃ are identical to or different fromeach other and are O, N or S.
 3. The polymer compound according to claim1, wherein Ar₁ is selected from the following compounds:


4. The polymer compound according to claim 1, wherein Ar₁′ and Ar₂ areselected from the following compounds:

wherein X is O, S, C(═O), CH(OH), S(═O)₂, Si(CH₃)₂, (CH₂)_(p) (in which1≦p≦10), (CF₂)_(q) (in which 1≦q≦10), C(CH₃)₂, C(CF₃)₂, or C(═O)NH; W isO, S or C(═O); and Z₁, Z₂ and Z₃ are identical to or different from eachother and are O, N or S.
 5. The polymer compound according to claim 1,wherein Ar₁′ and Ar₂ are selected from the following compounds:


6. The polymer compound according to claim 1, wherein Q is selected fromthe group consisting of CH₂, C(CH₃)₂, C(CF₃)₂, O, S, S(═O)₂ and C(═O).7. The polymer compound according to claim 1, wherein Ar₁ is

Ar₁′ is

Ar₂ is

and Q is C(CF₃)₂.
 8. The polymer compound according to claim 1, whereinthe polymer compound is treated by an acidic dopant.
 9. The polymercompound according to claim 8, wherein the acidic dopant is selectedfrom the group consisting of sulfuric acid, hydrochloric acid,phosphoric acid, nitric acid, HBrO₃, HClO₄, HPF₆, HBF₆,1-methyl-3-methylimidazolium cation (BMIM⁺) and mixtures thereof. 10.The polymer compound according to claim 1, wherein the polymer compoundincludes inorganic oxide selected from the group consisting of fumedsilica, zirconium oxide, tetraethoxy silane, montmorillonite clay andmixtures thereof.
 11. The polymer compound according to claim 1, whereinthe polymer compound includes inorganic filler selected from the groupconsisting of phosphotungstic acid (PWA), phosphomolybdenic acid,silicotungstic acid (SiWA), molybdophosphoric acid, silicomolybdic acid,phosphotin acid, zirconium phosphate (ZrP) and mixtures thereof.
 12. Thepolymer compound according to claim 1, wherein the polymer compound hasa fractional free volume (FFV) of 0.18 to 0.40.
 13. The polymer compoundaccording to claim 1, wherein the polymer compound has a d-spacing of0.58 to 0.80 nm.
 14. The polymer compound according to claim 1, whereinthe polymer compound has a cavity radius difference of 0.1 to 0.4 Åbetween maximum cavity radius and minimum cavity radius.
 15. A methodfor preparing the polymer compound of claim 1 comprising: thermallytreating polyimides represented by the following Formulae 15 to
 32.

In Formulae 15 to 32, Ar₁ is a tetravalent C₅-C₂₄ arylene group or atetravalent C₅-C₂₄ heterocyclic ring, which is substituted orunsubstituted with at least one substituent selected from the groupconsisting of C₁-C₁₀ alkyl, C₁-C₁₀ alkoxy, C₁-C₁₀ haloalkyl and C₁-C₁₀haloalkoxy, or two or more of which are fused together to form acondensation ring or covalently bonded to each other via a functionalgroup selected from the group consisting of O, S, C(═O), CH(OH), S(═O)₂,Si(CH₃)₂, (CH₂)_(p) (in which 1≦p≦10), (CF₂)_(q), (in which 1≦q≦10),C(CH₃)₂, C(CF₃)₂ and C(═O)NH; Ar₂ is a bivalent C₅-C₂₄ arylene group ora bivalent C₅-C₂₄ heterocyclic ring, which is substituted orunsubstituted with at least one substituent selected from the groupconsisting of C₁-C₁₀ alkyl, C₁-C₁₀ alkoxy, C₁-C₁₀ haloalkyl and C₁-C₁₀haloalkoxy, or two or more of which are fused together to form acondensation ring or covalently bonded to each other via a functionalgroup selected from the group consisting of O, S, C(═O), CH(OH), S(═O)₂,Si(CH₃)₂, (CH₂)_(p) (in which 1≦p≦10), (CF₂)_(q), (in which 1≦q≦10),C(CH₃)₂, C(CF₃)₂ and C(═O)NH; Q is O, S, C(═O), CH(OH), S(═O)₂,Si(CH₃)₂, (CH₂)_(p) (in which 1≦p≦10), (CF₂)_(q) (in which 1≦q≦10),C(CH₃)₂, C(CF₃)₂, C(═O)NH, C(CH₃)(CF₃), C₁-C₆ alkyl-substituted phenylor C₁-C₆ haloalkyl-substituted phenyl in which Q is linked to oppositeboth phenyl rings in the position of m-m, m-p, p-m or p-p; Y is —OH, —SHor —NH₂; Y′ is different from Y and is —OH, —SH or —NH₂; n is an integerfrom 20 to 200; m is an integer from 10 to 400; and l is an integer from10 to
 400. 16. The method according to claim 15, wherein the thermaltreatment is carried out at 350 to 500° C. for 1 minute to 12 hoursunder an inert atmosphere.
 17. The method according to claim 15, whereinthe thermal treatment is carried out at 400 to 450° C. for 10 minutes to2 hours under an inert atmosphere.
 18. The method according to claim 15,wherein the polyimides represented by Formulae 15 to 32 are obtained byimidization of polyamic acids represented by Formulae 33 to 50 below:

In Formulae 33 to 50, Ar₁, Ar₂, Q, Y, n, m and l are defined as above;and Y′ is different from Y and is —OH, —SH or —NH₂;
 19. The methodaccording to claim 19, wherein the imidization performs chemicalimidization method, thermal imidization method or solution-thermalimidization method.